Composite material of metal and rubber for use in industrial rubber articles

ABSTRACT

A composite material comprising a rubber composition and a metal material, wherein the rubber composition contains, per 100 parts by weight of rubber, a cobalt salt of an organic acid in an amount up to 0.5 parts by weight, 3 to 6 parts by weight of sulfur, and N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide as a vulcanization accelerator, and the metal material is provided with a plating of a ternary alloy consisting of copper, zinc, and nickel.

This application is a continuation, of application Ser. No. 08/043,607,filed on Apr. 5, 1993, which is a continuation of U.S. Ser. No.07/845,844, filed on Mar. 6, 1992, which is a continuation of U.S. Ser.No. 07/550,557 filed Jul. 10, 1990 which is a divisional application ofU.S. Ser. No. 07/266,580 filed Nov. 3, 1988, now all abandoned.

FIELD OF THE INVENTION

The present invention relates to a composite material comprising arubber material (or composition) and a metal material. Moreparticularly, the present invention relates to a composite material thatis adapted for use in industrial rubber articles such as tires forvehicles and conveyor belts and which retains good adhesion betweenmetal and rubber even after the latter's aging.

BACKGROUND OF THE INVENTION

The performance required of tires for vehicles, conveyor belts and otherindustrial rubber articles has become increasingly versatile. In thetires for vehicles, radial tires are extensively used not only as tiresfor passenger cars but also as tires for large cars such as trucks andbuses, and the useful life of tires has been remarkably extended byseveral reasons including the advances in the mixing technology of treadrubber. Large tires that have been used for large cars such as trucksand buses are retreaded after the end of their primary life so that theyare put to service for the secondary, and even tertiary, use. These usessometimes extend to several hundreds thousand kilometers and the beltsand carcasses of tires on vehicles are required to performsatisfactorily for this period.

In the above radial tires, rubber-coated steel cords are used to formthe belts or carcasses in order to improve the steering stability,structural durability, wear resistance and puncture resistance of thetires. With such tires, the adhesion between rubber material and metalmaterial can be a problem.

Rubber material normally adheres to metal material, when sulfur mixed inthe rubber material during vulcanization, reacts with copper in theplating on the metal material so as to form a sulfide at therubber-metal interface. When a tire is rolling on the road, hysteresisloss of the rubber material generates heat, and if the generated heat islarge adhesion between the rubber material and the metal material isbroken, and the coated rubber separates from the steel cord and this"separation" renders further rolling of the tire on the road impossible.

Further, the tire tread or sidewall may sometimes be damaged when thetire is rolling on the road. If the damage is deep enough to reach thesteel cord, moisture that has permeated the tire through the damagedpart will be vaporized by the heat generated during tire rolling on theroad, and the vapor (getting into the space between filaments in thesteel cord) will destroy the adhesion between the steel cord and thecoated rubber, thereby inducing "separation".

A further problem will occur if the tire is inflated with moisturecontaining air. The moisture will penetrate through innerliner of thetire to reach the steel cord and this may induce "separation" bybreaking the adhesion between the coated rubber and the steel cord.

With a view to avoiding these phenomena, various techniques have beenproposed that are chiefly intended to improve the adhesion between therubber and the steel cords. One of the techniques proposed concerns thecompounding techniques of rubber material with which steel cords arecoated. It was discovered as early as in the nineteen-fifties that theadhesion between the rubber and the steel cords could be improved byincorporating cobalt salts of organic acids in the rubber material, andmany studies have been conducted regarding the quantity and type of suchthe cobalt salts to be added. For example, JP-A-60-42440 (the term"JP-A" as used herein refers to a "published unexamined Japanese patentapplication") shows that improved adhesion can be attained by optimizingthe quantities of sulfur and cobalt salts of organic acids. Anotherapproach has been to use the HRH based composition mixing white carbon,resorcin and hexamethylenetetramine. Drawbacks of the above cobaltmethod include that if cobalt salts of organic acids are added in largeamounts, unvulcanized rubber will be deteriorated, or the deteriorationof adhesive power due to thermal aging will occur, either on account ofhot or prolonged vulcanization or rolling of the tire on the road for adistance of many hundred kilometers. The HRH composition's principaldrawbacks are that they cause problems during production such asenvironmental pollution and rubber scorching.

The second approach that has been taken to improve the adhesion betweenthe rubber and the steel cords is directed at the plating layer to bedeposited on a metal material. JP-B-51-8389 (the term "JP-B" as usedherein refers to an "examined Japanese patent publication") andJP-A-55-105548 disclose a plating layer containing nickel. Alloyplatings containing three or four metals are disclosed in JP-A-55-45884,JP-A-55-71887, JP-A-55-105548, JP-A-56-82604, JP-A-54-89940,JP-A-61-243194, JP-A-61-72545, etc.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a composite materialcomprising a rubber composition (material) and a metal material that issuccessfully improved over the prior art not only in adhesion afterthermal aging but also in adhesion after wet heat aging (hereinafterreferred to as "heat resistance" and "wet heat resistance",respectively) without causing other problems, in particular, those whichhave conventionally been encountered during production. This object ofthe present invention is attained by combining a metal material havingan improved plating layer and a rubber material having a compoundformulation suitable for this metal material. More specifically, thepresent invention provides a composite material comprising a rubbercomposition and a metal material, wherein the rubber compositioncontains, per 100 parts by weight of rubber, 0 to 0.5 part by weight ofa cobalt salt of an organic acid, 3 to 6 parts by weight of sulfur, andN-oxydiethylene-2-benzothiazolylsulfenamide orN-tert-butyl-2-benzothiazolylsulfenamide as a vulcanization accelerator,and the metal material is provided with a plating of a ternary alloyconsisting of copper, zinc, and nickel.

DETAILED DESCRIPTION OF THE INVENTION

Examples of the cobalt salts of organic acids that can be used in thepresent invention include cobalt naphthenate, cobalt oleate, cobaltmaleate and cobalt stearate. In order to ensure high initial strength ofadhesion, these cobalt salts of organic acids preferably contain cobaltin an amount of 8 to 10 wt %.

The shape of the metal material can be freely chosen in accordance withthe type of industrial article to which the composite material of thepresent invention is applied. If it is applied to conveyor belts ortires for vehicles, the metal material is preferably used in the form ofcords, particularly in the form of steel cords.

It has generally been held that high initial strength of adhesion is notattainable unless cobalt salts of organic acids are used in amountsexceeding 0.5 part by weight per 100 parts by weight of rubber. However,in accordance with the present invention,N-oxydiethylene-2-benzothiazolylsulfenamide orN-tert-butyl-2-benzothiazolylsulfenamide is added to rubber as avulcanization accelerator and the resulting rubber composition iscombined with a metal material provided with a plating of a ternaryalloy consisting of copper, zinc or nickel, and this ensuressatisfactory strength of adhesion even if a cobalt salt of an organicacid is present in an amount of not more than 0.5 part by weight, andparticularly the satisfactory strength of adhesion is ensured even in anextreme case where such the cobalt salts of organic acids are entirelyabsent. Therefore, the present invention is capable of avoiding theproblems during production and aging after vulcanization which haveoccurred in the prior art on account of the incorporation of cobaltsalts of organic acids in large amounts.

If the rubber composition of the present invention contains less than 3parts by weight of sulfur, satisfactory initial strength of adhesion isnot attainable. If the sulfur content exceeds 6 parts by weight, theheat resistance of the resulting composite material will be impaired.Accordingly, the amount of sulfur used in the rubber composition of thepresent invention is generally 3 to 6 parts by weight and preferably 3.5to 5.5 parts by weight, per 100 parts by weight of rubber.

The vulcanization accelerator is preferably used in the presentinvention in an amount of from 0.5 to 2 parts by weight and morepreferably from 0.5 to 1.5 parts by weight, per 100 parts by weight ofrubber. If the vulcanization accelerator is incorporated in an amount ofless than 0.5 part by weight, the speed of vulcanization tends to beslow and poor adhesion often results. If the content of thevulcanization accelerator exceeds 2 parts by weight, the modulus of therubber becomes so high as to occasionally cause adverse effects on theadhesion between the rubber material and the metal material or thebreaking strength of the rubber itself.

The metal material of the composite material of the present inventionmust be plated with a ternary alloy consisting of copper, zinc andnickel. An advantageous composition of this plating alloy consists of 60to 75 wt % copper, 4 to 10 wt % nickel and the balance being zinc. Ifthe copper content is less than 60 wt %, desired initial strength ofadhesion is not attainable. If copper is present in an amount exceeding75 wt %, the contents of nickel and zinc are too much reduced to ensuresatisfactory heat and wet heat resistance. Nickel need not be present ina large amount and a required minimum amount is preferably 4 wt %. Ifthe nickel content exceeds 10 wt %, the reaction of adhesion isinhibited and the necessary initial strength of adhesion is difficult toobtain.

The following example is provided for the purpose of furtherillustrating the present invention but the present invention is not tobe construed as being limited thereto.

EXAMPLE

Rubber compositions having the basic mixing preparation (recipe) shownin Table 1 were prepared by varying the amounts of sulfur and cobaltstearate as well as the type and amount of vulcanization accelerator, asshown in Table 2.

                  TABLE 1                                                         ______________________________________                                        Ingredients          Parts by weight                                          ______________________________________                                        Natural rubber       100                                                      HAF (High Abrasion Furnance)                                                                       50                                                       Zinc white (ZnO)     8                                                        Antiaging agent*     2                                                        Cobalt stearate**    Variable                                                                      (see Table 2)                                            Sulfur               Variable                                                                      (see Table 2)                                            Vulcanization accelerator                                                                          Variable                                                                      (see Table 2)                                            ______________________________________                                         *2,2,4-Trimethyl-1,2-dihydroquinoline polymer                                 **Cobalt content = 9 wt %                                                

In Table 2, Rubber Composition Nos. 1 to 18 were those prepared inaccordance with the present invention.

                  TABLE 2                                                         ______________________________________                                        Rubber Composition (mixing ratio)                                             Sam- Cobalt Stearate                                                                           Sulfur     Vulcanization Accelerator                         ple  Amount      Amount            Amount                                     No.  (pts. by wt.)                                                                             (pts. by wt.)                                                                            Type*  (pts. by wt.)                              ______________________________________                                        1    0           3.5        A      1.0                                        2    0           4.5        "      1.0                                        3    0           5.5        "      1.0                                        4    0.5         3.5        "      1.0                                        5    0.5         4.5        "      1.0                                        6    0.5         5.5        "      1.0                                        7    0           3.5        B      1.0                                        8    0           4.5        "      1.0                                        9    0           5.5        "      1.0                                        10   0.5         3.5        "      1.0                                        11   0.5         4.5        "      1.0                                        12   0.5         5.5        "      1.0                                        13   0           4.5        A      0.5                                        14   0           4.5        "      2.0                                        15   0           4.5        "      2.5                                        16   0           4.5        B      0.5                                        17   0           4.5        "      2.0                                        18   0           4.5        "      2.5                                        19   1.0         3.0        C      1.0                                        20   1.0         3.5        "      1.0                                        21   1.0         5.0        "      1.0                                        22   1.0         5.5        C      1.0                                        23   1.0         6.5        "      1.0                                        24   1.0         7.0        "      1.0                                        25   1.5         2.5        "      1.0                                        26   1.5         4.5        "      1.0                                        27   1.5         6.5        "      1.0                                        28   2.0         3.5        "      1.0                                        29   2.0         4.0        "      1.0                                        30   2.0         5.5        "      1.0                                        31   2.0         6.0        "      1.0                                        32   2.5         2.5        "      1.0                                        33   2.5         4.5        "      1.0                                        34   3.0         3.0        "      1.0                                        35   3.0         5.0        "      1.0                                        36   3.0         7.0        "      1.0                                        37   4.0         4.0        "      1.0                                        38   4.0         6.0        "      1.0                                        39   5.0         3.0        "      1.0                                        40   5.0         5.0        "      1.0                                        41   5.0         7.0        "      1.0                                        42   0           4.0        "      1.0                                        43   0           5.5        "      1.0                                        44   0           6.0        C      1.0                                        45   0           7.0        "      1.0                                        46   0.5         2.5        "      1.0                                        47   0.5         6.5        "      1.0                                        48   2.0         8.0        "      1.0                                        49   4.0         9.0        "      1.0                                        50   6.0         6.0        "      1.0                                        51   7.0         4.0        "      1.0                                        52   7.0         10.0       "      1.0                                        ______________________________________                                         *A: NOxydiethylene-2-benzothiazolylsulfenamide (Invention)                    B: Ntert-Butyl-2-benzothiazolylsulfenamide (Invention)                        C: N,NDicyclohexyl-2-benzothiazolylsulfenamide (Comparison)              

Subsequently, steel cords (1×5/0.25) were plated with alloys having thecompositions shown in Table 3.

                  TABLE 3                                                         ______________________________________                                                  Composition of Plating                                              Steel Cord                                                                              Alloy (wt %)                                                        Sample No.                                                                              Copper  Zinc      Nickel                                                                              Remarks                                     ______________________________________                                        A         65      35        0     Comparison                                  B         65      33        2     Invention                                   C         65      31        4     "                                           D         65      29        6     "                                           E         65      27        8     "                                           F         65      25        10    "                                           G         65      10        25    "                                           H         65       5        35    "                                           ______________________________________                                    

The rubber compositions shown in Table 2 were combined in various wayswith the steel cords shown in Table 3 and the resulting mixingcompositions were vulcanized under predetermined conditions, followed byaging under the conditions shown in Table 4. Thereafter, the rubbermaterial was peeled apart mechanically from the cords and the peelforce, i.e., the force required to cause separation between the rubberand the cord, was measured. At the same time, the state of rubberadhered to the surface of cords was visually evaluated on a 10-pointscoring basis. The results are shown in Table 5, as well as in Table 6.The greater the values shown in these tables, the better are theresults.

                  TABLE 4                                                         ______________________________________                                                Aging Condition                                                                                       Relative                                      Aging     Time       Temperature                                                                              Humidity                                      Condition (hr)       (°C.)                                                                             (%)                                           ______________________________________                                        (a)        0         --         --                                            (b)       400         80         95                                           (c)       24         120        100                                           (d)       96         120        --                                            ______________________________________                                    

Condition (a) was used for measuring the initial strength of adhesion;conditions (b) and (c) were used for measuring wet heat resistance; andcondition (d) was used for measuring heat resistance.

Among the combinations shown in Table 5 and Table 6, those consisting ofRubber Composition Samples 1 to 18 and Steel Cord Samples B to Hprovided composite materials within the scope of the present invention.

Table 5 shows the results of visual evaluation of rubber adhesion on a10-point scoring basis and the greater the values shown in these tables,the better are the results.

Table 6 shows the results of measurements of peeling force.

                                      TABLE 5                                     __________________________________________________________________________    (State of Rubber Adhesion)                                                    __________________________________________________________________________    Steel                                                                             Test   Rubber Composition                                                 Cord                                                                              Condition                                                                            1 2 3 4 5 6 7 8 9 10                                                                              11                                                                              12                                                                              13                                                                              14                                                                              15                                                                              16                                                                              17                                                                              18                                                                              19                                                                              20                                                                              21                                                                              22                                                                              23                                                                              24                                                                              25                                                                              26               __________________________________________________________________________    A   (a)    --                                                                              10                                                                              --                                                                              --                                                                              10                                                                              --                                                                              6 7 8 7 8 9 8 10                                                                              7 8 8       7                                                                             9                                                                             9                                                                             10                                                                              10                                                                              10                                                                              10                                                                              9  10                  (b)    --                                                                              10                                                                              --                                                                              --                                                                              10                                                                              --                                                                              6 7 7 7 7 8 7 8 7 7 7       7                                                                             5                                                                             8                                                                             5 8 8 6 8  8                   (c)    --                                                                              7 --                                                                              --                                                                              8 --                                                                              4 5 5 6 7 7 6 7 6 6 6       6                                                                             5                                                                             8                                                                             6 9 8 6 7  6                   (d)    --                                                                              6 --                                                                              --                                                                              6 --                                                                              6 6 6 6 6 5 6 6 6 6 5       6                                                                             7                                                                             7                                                                             7 7 7 6 5  5               B   (a)    10                                                                              10                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              9       --                                                                            9                                                                             --                                                                            10                                                                              --                                                                              --                                                                              10                                                                              -- --                  (b)    9 10                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              9 --                                                                              --                                                                              9       --                                                                            4                                                                             --                                                                            5 --                                                                              --                                                                              5 -- --                  (c)    7 8 --                                                                              --                                                                              9 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              8 --                                                                              --                                                                              8       --                                                                            8                                                                             --                                                                            8 --                                                                              --                                                                              6 -- --                  (d)    7 7 --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              6       --                                                                            7                                                                             --                                                                            8 --                                                                              --                                                                              6 -- --              C   (a)    10                                                                              10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              9       --                                                                            8                                                                             --                                                                            10                                                                              --                                                                              --                                                                              10                                                                              -- --                  (b)    10                                                                              10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            5                                                                             --                                                                            7 --                                                                              --                                                                              7 -- --                  (c)    9 10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              9 10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              9       --                                                                            7                                                                             --                                                                            9 --                                                                              --                                                                              7 -- --                  (d)    9 10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            8                                                                             --                                                                            9 --                                                                              --                                                                              6 -- --              D   (a)    9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              9 10                                                                              10                                                                              9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10      10                                                                            8                                                                             10                                                                            10                                                                              9 9 9 7  8                   (b)    10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10      10                                                                            4                                                                             9                                                                             9 10                                                                              10                                                                              6 8  8                   (c)    9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10      10                                                                            8                                                                             9                                                                             10                                                                              9 9 8 8  9                   (d)    9 10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              10      10                                                                            8                                                                             7                                                                             9 7 7 6 6  7               E   (a)    9 10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            7                                                                             --                                                                            10                                                                              --                                                                              --                                                                              9 -- --                  (b)    10                                                                              10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            6                                                                             --                                                                            8 --                                                                              --                                                                              6 -- --                  (c)    10                                                                              10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            6                                                                             --                                                                            10                                                                              --                                                                              --                                                                              8 -- --                  (d)    9 10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            7                                                                             --                                                                            9 --                                                                              --                                                                              6 -- --              F   (a)    9 9 10                                                                              --                                                                              10                                                                              --                                                                              9 10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              9 --                                                                              --                                                                              9       --                                                                            6                                                                             --                                                                            10                                                                              --                                                                              --                                                                              --                                                                              -- --                  (b)    9 10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              9       --                                                                            5                                                                             --                                                                            7 --                                                                              --                                                                              --                                                                              -- --                  (c)    10                                                                              10                                                                              10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            5                                                                             --                                                                            9 --                                                                              --                                                                              --                                                                              -- --                  (d)    9 9 10                                                                              --                                                                              10                                                                              --                                                                              10                                                                              10                                                                              10                                                                              --                                                                              --                                                                              --                                                                              --                                                                              10                                                                              --                                                                              --                                                                              10      --                                                                            6                                                                             --                                                                            9 --                                                                              --                                                                              --                                                                              -- --              G   (a)    --                                                                              --                                                                              --                                                                              --                                                                              8 --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              6 7 7 6 6       7                                                                             --                                                                            --                                                                            --                                                                              7 --                                                                              --                                                                              -- --                  (b)    --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              7 --                                                                              --                                                                              --                                                                              7 7 7 7 7       7                                                                             --                                                                            --                                                                            --                                                                              8 --                                                                              --                                                                              -- --                  (c)    --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              6 6 6 6 6       6                                                                             --                                                                            --                                                                            --                                                                              8 --                                                                              --                                                                              -- --                  (d)    --                                                                              --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              6 6 6 6 6       6                                                                             --                                                                            --                                                                            --                                                                              5 --                                                                              --                                                                              -- --              H   (a)    --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (b)    --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (c)    --                                                                              --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              6 --                                                                              --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (d)    --                                                                              --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              5 --                                                                              --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --              __________________________________________________________________________    Steel                                                                             Test   Rubber Composition                                                 Cord                                                                              Condition                                                                            27                                                                              28                                                                              29                                                                              30                                                                              31                                                                              32                                                                              33                                                                              34                                                                              35                                                                              36                                                                              37                                                                              38                                                                              39                                                                              40                                                                              41                                                                              42                                                                              43                                                                              44                                                                              45                                                                              46                                                                              47                                                                              48                                                                              49                                                                              50                                                                              51                                                                              52               __________________________________________________________________________    A   (a)    10                                                                              10                                                                              10                                                                              10                                                                              10                                                                              9 9 9 10                                                                              10                                                                              9 10                                                                              9 9 9 9 7       10                                                                            9                                                                             7                                                                             8 10                                                                              9 9 8  7                   (b)    9 8 7 8 9 7 7 5 8 7 6 7 4 4 2 1 6       1                                                                             9                                                                             9                                                                             8 7 4 3 1  1                   (c)    6 5 5 5 6 5 4 6 7 7 4 4 2 2 1 1 5       1                                                                             9                                                                             9                                                                             8 3 1 4 1  1                   (d)    4 4 6 4 6 4 4 5 5 4 4 3 2 1 1 8 5       7                                                                             7                                                                             8                                                                             7 2 1 1 1  1               B   (a)    --                                                                              --                                                                              10                                                                              --                                                                              10                                                                              --                                                                              --                                                                              9 10                                                                              10                                                                              9 10                                                                              8 10                                                                              10                                                                              8 --      9                                                                             --                                                                            --                                                                            --                                                                              10                                                                              9 9 9  6                   (b)    --                                                                              --                                                                              8 --                                                                              9 --                                                                              --                                                                              6 7 7 7 6 4 3 3 1 --      2                                                                             --                                                                            --                                                                            --                                                                              7 5 4 1  1                   (c)    --                                                                              --                                                                              8 --                                                                              7 --                                                                              --                                                                              3 4 4 5 6 2 2 2 1 --      1                                                                             --                                                                            --                                                                            --                                                                              4 1 5 3  1                   (d)    --                                                                              --                                                                              7 --                                                                              6 --                                                                              --                                                                              4 4 4 3 3 2 2 2 8 --      4                                                                             --                                                                            --                                                                            --                                                                              2 1 2 1  1               C   (a)    --                                                                              --                                                                              10                                                                              --                                                                              10                                                                              --                                                                              --                                                                              8 10                                                                              10                                                                              9 10                                                                              8 10                                                                              10                                                                              7 --      9                                                                             --                                                                            --                                                                            --                                                                              10                                                                              9 9 8  6                   (b)    --                                                                              --                                                                              8 --                                                                              9 --                                                                              --                                                                              6 7 6 7 6 5 5 4 1 --      2                                                                             --                                                                            --                                                                            --                                                                              6 5 4 2  1                   (c)    --                                                                              --                                                                              7 --                                                                              7 --                                                                              --                                                                              3 4 4 5 6 2 2 2 1 --      1                                                                             --                                                                            --                                                                            --                                                                              4 1 5 2  1                   (d)    --                                                                              --                                                                              6 --                                                                              6 --                                                                              --                                                                              4 4 4 3 2 2 2 2 7 --      7                                                                             --                                                                            --                                                                            --                                                                              1 1 2 1  1               D   (a)    8 9 10                                                                              8 10                                                                              9 9 8 10                                                                              10                                                                              9 9 8 10                                                                              10                                                                              7 6       8                                                                             7                                                                             6                                                                             10                                                                              9 8 9 8  6                   (b)    8 7 8 7 9 6 7 5 6 6 8 7 5 6 5 2 7       2                                                                             9                                                                             9                                                                             9 7 5 4 2  1                   (c)    8 7 7 6 7 7 6 3 4 4 6 6 2 2 2 1 8       2                                                                             9                                                                             9                                                                             9 4 1 6 2  1                   (d)    6 6 7 6 6 5 6 3 4 4 3 2 2 2 2 7 7       7                                                                             6                                                                             7                                                                             8 2 1 1 1  1               E   (a)    --                                                                              --                                                                              10                                                                              --                                                                              10                                                                              --                                                                              --                                                                              8 10                                                                              10                                                                              9 9 7 10                                                                              10                                                                              6 --      8                                                                             --                                                                            --                                                                            --                                                                              9 8 8 8  6                   (b)    --                                                                              --                                                                              7 --                                                                              8 --                                                                              --                                                                              6 6 6 8 7 5 7 5 2 --      2                                                                             --                                                                            --                                                                            --                                                                              7 5 3 2  1                   (c)    --                                                                              --                                                                              8 --                                                                              8 --                                                                              --                                                                              3 5 5 6 7 2 2 2 1 --      7                                                                             --                                                                            --                                                                            --                                                                              4 1 5 3  1                   (d)    --                                                                              --                                                                              6 --                                                                              5 --                                                                              --                                                                              4 4 4 3 3 2 2 2 6 --      7                                                                             --                                                                            --                                                                            --                                                                              2 1 2 1  1               E   (a)    --                                                                              --                                                                              10                                                                              --                                                                              9 --                                                                              --                                                                              8 10                                                                              10                                                                              8 9 7 10                                                                              10                                                                              6 --      7                                                                             --                                                                            --                                                                            --                                                                              8 7 8 8  6                   (b)    --                                                                              --                                                                              7 --                                                                              8 --                                                                              --                                                                              4 5 6 8 7 5 8 5 2 --      2                                                                             --                                                                            --                                                                            --                                                                              7 3 2 2  1                   (c)    --                                                                              --                                                                              8 --                                                                              9 --                                                                              --                                                                              4 4 4 6 7 3 2 2 1 --      2                                                                             --                                                                            --                                                                            --                                                                              3 1 5 2  1                   (d)    --                                                                              --                                                                              7 --                                                                              4 --                                                                              --                                                                              4 5 5 2 3 2 2 2 6 --      5                                                                             --                                                                            --                                                                            --                                                                              2 1 1 2  1               G   (a)    --                                                                              --                                                                              4 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              5 6 7 8 7 --                                                                              4       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (b)    --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              7 7 7 7 7 --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (c)    --                                                                              --                                                                              5 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              6 6 6 6 6 --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (d)    --                                                                              --                                                                              4 --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              6 6 6 6 6 --                                                                              5       --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --              H   (a)    --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --      --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (b)    --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --      --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (c)    --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --      --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --                  (d)    --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --      --                                                                            --                                                                            --                                                                            --                                                                              --                                                                              --                                                                              --                                                                              -- --              __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________    (Peeling Force: kgf/cm.sup.2)                                                 __________________________________________________________________________    Steel                                                                             Test  Rubber Composition                                                  Cord                                                                              Condition                                                                           1  2  3  4  5  6  8  9  10 13 14 15 16 17                           __________________________________________________________________________    A   (a)   -- 6.2                                                                              -- -- 6.3                                                                              -- -- 5.7                                                                              -- 5.9                                                                              6.3                                                                              6.3                                                                              5.8                                                                              5.7                              (b)   -- 5.4                                                                              -- -- 5.4                                                                              -- -- 4.3                                                                              -- 5.0                                                                              5.1                                                                              4.8                                                                              4.2                                                                              4.1                              (c)   -- 4.5                                                                              -- -- 4.9                                                                              -- -- 3.1                                                                              -- 4.6                                                                              4.5                                                                              4.0                                                                              3.2                                                                              3.0                              (d)   -- 3.6                                                                              -- -- 3.5                                                                              -- -- 3.2                                                                              -- 3.5                                                                              3.0                                                                              2.8                                                                              3.2                                                                              2.8                          B   (a)   -- 6.2                                                                              -- -- 6.2                                                                              -- -- -- -- -- 6.2                                                                              -- -- 6.0                              (b)   -- 5.4                                                                              -- -- 5.5                                                                              -- -- -- -- -- 5.4                                                                              -- -- 5.2                              (c)   -- 4.9                                                                              -- -- 4.9                                                                              -- -- -- -- -- 4.7                                                                              -- -- 4.7                              (d)   -- 3.8                                                                              -- -- 3.6                                                                              -- -- -- -- -- 3.5                                                                              -- -- 3.3                          C   (a)   6.1                                                                              6.2                                                                              6.3                                                                              -- 6.3                                                                              -- 6.1                                                                              6.2                                                                              6.3                                                                              -- 6.3                                                                              -- -- 6.2                              (b)   5.4                                                                              5.4                                                                              5.4                                                                              -- 5.5                                                                              -- 5.3                                                                              5.3                                                                              5.4                                                                              -- 5.5                                                                              -- -- 5.4                              (c)   5.0                                                                              5.0                                                                              5.1                                                                              -- 5.0                                                                              -- 5.1                                                                              5.0                                                                              5.1                                                                              -- 4.9                                                                              -- -- 4.8                              (d)   4.5                                                                              4.5                                                                              4.3                                                                              -- 4.4                                                                              -- 4.5                                                                              4.6                                                                              4.4                                                                              -- 4.3                                                                              -- -- 4.5                          D   (a)   6.0                                                                              6.2                                                                              6.3                                                                              6.3                                                                              6.4                                                                              6.5                                                                              6.1                                                                              6.2                                                                              6.3                                                                              -- 6.3                                                                              -- -- 6.3                              (b)   5.3                                                                              5.4                                                                              5.5                                                                              5.5                                                                              5.5                                                                              5.4                                                                              5.2                                                                              5.0                                                                              5.0                                                                              -- 5.4                                                                              -- -- 5.3                              (c)   5.2                                                                              5.0                                                                              5.2                                                                              5.2                                                                              5.0                                                                              5.1                                                                              5.3                                                                              5.2                                                                              5.1                                                                              -- 5.1                                                                              -- -- 5.0                              (d)   4.5                                                                              4.6                                                                              4.5                                                                              4.5                                                                              4.4                                                                              4.3                                                                              4.5                                                                              4.6                                                                              4.4                                                                              -- 4.4                                                                              -- -- 4.5                          E   (a)   6.0                                                                              6.2                                                                              6.3                                                                              -- 6.5                                                                              -- 6.0                                                                              6.1                                                                              6.3                                                                              -- 6.5                                                                              -- -- 6.3                              (b)   5.4                                                                              5.4                                                                              5.4                                                                              -- 5.3                                                                              -- 5.3                                                                              5.4                                                                              5.2                                                                              -- 5.4                                                                              -- -- 5.4                              (c)   5.1                                                                              5.1                                                                              5.1                                                                              -- 5.0                                                                              -- 5.1                                                                              5.0                                                                              5.1                                                                              -- 5.1                                                                              -- -- 5.0                              (d)   4.6                                                                              4.6                                                                              4.4                                                                              -- 4.5                                                                              -- 4.5                                                                              4.6                                                                              4.3                                                                              -- 4.4                                                                              -- -- 4.3                          F   (a)   5.8                                                                              6.0                                                                              6.3                                                                              -- 6.4                                                                              -- 5.9                                                                              6.0                                                                              6.2                                                                              -- 6.4                                                                              -- -- 6.3                              (b)   5.3                                                                              5.3                                                                              5.4                                                                              -- 5.4                                                                              -- 5.3                                                                              5.4                                                                              5.3                                                                              -- 5.2                                                                              -- -- 5.1                              (c)   5.0                                                                              5.0                                                                              5.1                                                                              -- 5.1                                                                              -- 5.1                                                                              5.1                                                                              5.2                                                                              -- 5.0                                                                              -- -- 5.0                              (d)   4.3                                                                              4.4                                                                              4.2                                                                              -- 4.5                                                                              -- 4.3                                                                              4.4                                                                              4.2                                                                              -- 4.3                                                                              -- -- 4.2                          G   (a)   -- 5.5                                                                              -- -- 5.7                                                                              -- -- 5.0                                                                              -- -- 5.5                                                                              -- -- 5.4                              (b)   -- 4.4                                                                              -- -- 4.2                                                                              -- -- 4.4                                                                              -- -- 4.4                                                                              -- -- 4.4                              (c)   -- 4.5                                                                              -- -- 4.2                                                                              -- -- 3.4                                                                              -- -- 4.0                                                                              -- -- 4.0                              (d)   -- 3.4                                                                              -- -- 3.1                                                                              -- -- 3.3                                                                              -- -- 3.1                                                                              -- -- 3.0                          H   (a)   -- 5.0                                                                              -- -- 5.3                                                                              -- -- -- -- -- 5.2                                                                              -- -- 5.3                              (b)   -- 4.2                                                                              -- -- 4.0                                                                              -- -- -- -- -- 4.0                                                                              -- -- 4.1                              (c)   -- 4.3                                                                              -- -- 3.9                                                                              -- -- -- -- -- 3.9                                                                              -- -- 3.8                              (d)   -- 3.0                                                                              -- -- 2.9                                                                              -- -- -- -- -- 2.9                                                                              -- -- 2.8                          __________________________________________________________________________    Steel                                                                             Test   Rubber Composition                                                 Cord                                                                              Condition                                                                            18                                                                              20 22 23 25 26 27 30 32 33 43 45 46 47                           __________________________________________________________________________    A   (a)    5.7                                                                             -- 6.2                                                                              -- -- -- -- -- -- -- 5.5                                                                              -- -- --                               (b)    4.0                                                                             -- 4.8                                                                              -- -- -- -- -- -- -- 4.2                                                                              -- -- --                               (c)    2.9                                                                             -- 5.0                                                                              -- -- -- -- -- -- -- 3.1                                                                              -- -- --                               (d)    2.5                                                                             -- 3.7                                                                              -- -- -- -- -- -- -- 3.0                                                                              -- -- --                           B   (a)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (b)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (c)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (d)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                           C   (a)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (b)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (c)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (d)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                           D   (a)    --                                                                              6.2                                                                              6.0                                                                              6.3                                                                              6.2                                                                              6.3                                                                              6.1                                                                              6.0                                                                              6.9                                                                              6.0                                                                              5.3                                                                              6.2                                                                              5.7                                                                              6.3                              (b)    --                                                                              4.6                                                                              5.1                                                                              4.3                                                                              4.7                                                                              4.5                                                                              4.4                                                                              4.0                                                                              4.2                                                                              3.9                                                                              4.4                                                                              4.7                                                                              4.9                                                                              4.5                              (c)    --                                                                              5.0                                                                              5.0                                                                              5.2                                                                              5.0                                                                              5.0                                                                              5.0                                                                              5.2                                                                              5.2                                                                              5.0                                                                              5.0                                                                              5.0                                                                              5.0                                                                              5.2                              (d)    --                                                                              4.0                                                                              3.7                                                                              4.0                                                                              3.6                                                                              4.2                                                                              3.1                                                                              3.1                                                                              3.0                                                                              2.9                                                                              3.8                                                                              4.0                                                                              4.1                                                                              3.2                          E   (a)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (b)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (c)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (d)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                           F   (a)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (b)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (c)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (d)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                           G   (a)    --                                                                              -- 5.6                                                                              -- -- -- -- -- -- -- 4.8                                                                              -- -- --                               (b)    --                                                                              -- 4.7                                                                              -- -- -- -- -- -- -- 4.0                                                                              -- -- --                               (c)    --                                                                              -- 4.9                                                                              -- -- -- -- -- -- -- 3.0                                                                              -- -- --                               (d)    --                                                                              -- 3.0                                                                              -- -- -- -- -- -- -- 3.1                                                                              -- -- --                           H   (a)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (b)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (c)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                               (d)    --                                                                              -- -- -- -- -- -- -- -- -- -- -- -- --                           __________________________________________________________________________

The composite materials prepared in accordance with the presentinvention exhibited satisfactory results under all of the conditionsemployed. Rubber Composition Nos. 1 to 3, 7 to 9, and 13 to 18 enabledthe preparation of composite materials that ensured satisfactoryadhesion without employing any cobalt salt of organic acids. Thisadvantage was especially noticeable when the rubber compositionsspecified above were combined with Steel Cord Samples C to F.

The composite material of the present invention ensures improvedadhesion between a rubber material and a metal material throughout theperiod of its use including from the initial stage to after aging byheat or wet heat. In addition, this composite material solved all of theproblems conventionally encountered during production such asenvironmental pollution and rubber scorching.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A composite material comprising a rubbercomposition and a metal material, wherein said rubber compositionconsists essentially of per 100 parts by weight of rubber, a cobalt saltof a carboxylic acid wherein said cobalt salt of said carboxylic acidcontains 8 to 10 wt % of cobalt in said salt, andN-oxydiethylene-2-benzothiazolylsulfenamide orN-tert-butyl-2-benzothiazolylsulfenamide as a vulcanization accelerator,and said metal material is provided with a plating of a tertiary alloyconsisting of 60 to 75% wt % copper, 4-10 wt % nickel, and the balancezinc; andwherein the cobalt salt of the carboxylic acid must be presentin an amount of up to 0.5 parts by weight.
 2. A composite material asclaimed in claim 1, wherein said vulcanization accelerator is present inan amount of 0.5 to 2 parts by weight per 100 parts by weight of rubber.